Apparatus for generating a current in a pool

ABSTRACT

An apparatus for generating a current in a pool, the apparatus including: 
     a) a shell including an upwardly extending intake chamber in fluid communication with the pool, the intake chamber having a liquid intake zone located in a lower end of the intake chamber; 
     b) an axial pump having an upstream suction-side and a downstream discharge-side, the pump located at an upper end of the intake chamber, the pump having a guide means arranged to direct liquid to flow longitudinally in the discharge-side channel substantially without swirling, the guide means being located downstream of the pumping element; and 
     c) drive means adapted to drive the drive shaft, wherein driving the drive shaft produces a discharge of liquid through the discharge-side outlet, to create a current in the pool for a swimmer to swim against.

RELATED APPLICATION

This application claims priority under 35 U.S.C. §119 from Australian Provisional Patent Application No. 2008904719, which was filed on Sep. 10, 2008, and the complete disclosure of which is hereby incorporated by reference.

FIELD OF THE INVENTION

This invention relates to apparatus for generating a current in a swimming pool or other vessel containing a liquid such as water.

BACKGROUND TO THE INVENTION

These have previously been proposed various types of apparatus for generating water currents in swimming pools whereby the water current acts as resistance to a swimmer so that swimming exercises can be carried out in a pool of quite short length. Hitherto, most types of water current generating apparatus for swimming pools have consisted of a water inlet and intake pipe mounted in a wall of the swimming pool, a separate outlet pipe and water outlet mounted in another location of the swimming pool and pump or jet means for receiving water from the inlet pipe and arranged to forcibly eject the water through the outlet pipe and water outlet to create a water current in the swimming pool. This type of apparatus, however, suffers from the disadvantage that separate mountings for the intake and outlet pipes and for the pump are required to be made in the swimming pool.

It is therefore desirable to provide water current generating apparatus for swimming pools and the like in which one or more disadvantages of prior art apparatus are alleviated. It is also desirable to provide water current generating apparatus of a relatively simple construction which can be readily installed in the wall of a swimming pool or the like.

SUMMARY OF THE INVENTION

A first aspect of the invention provides an apparatus for generating a current in a liquid-containing vessel having an exercise zone, against which current a swimmer may swim, the apparatus including:

a) a shell, the shell including:

-   -   i) an upwardly extending intake chamber in fluid communication         with the vessel, the intake chamber having a liquid intake zone         located in a lower end of the intake chamber;

b) an axial pump having an upstream suction-side and a downstream discharge-side, the pump located at an upper end of the intake chamber, the pump having:

-   -   i) a pump housing having:     -   a suction-side inlet in fluid communication with the intake         chamber,     -   a substantially horizontal discharge-side channel having an open         front end forming a discharge-side outlet, and     -   a suction-side end wall remote from the suction-side inlet and         discharge-side outlet;     -   ii) a substantially horizontal drive shaft defining the         longitudinal axis of the pump;     -   iii) a pumping element for expelling liquid via the         discharge-side channel and discharge-side outlet into the         exercise zone;     -   iv) a guide means arranged to direct liquid to flow         longitudinally in the discharge-side channel substantially         without swirling, the guide means being located downstream of         the pumping element;

c) drive means adapted to drive the drive shaft, wherein driving the drive shaft produces a discharge of liquid through the discharge-side outlet, to create a current in the exercise zone for a swimmer to swim against.

Advantageously, this enables a high volume of liquid to be delivered to the exercise zone in a generally horizontal direction, at a low pressure and with low turbulence. Liquid is returned to the pump via the intake zone which is located remote from the discharge zone, and hence the current generated through the exercise zone for swimming against is generally unaffected by the return current as they are vertically separated. Furthermore, by providing a large intake chamber, rather than a pipe, it is possible to provide a large intake zone and to avoid a throttling effect such as may be observed at pipe take-offs. This allows the liquid to be drawn into the intake chamber at a low velocity and removes or reduces the suction effect felt at the intake zone. Thus, the return current may also be of low velocity and thus of low likelihood to impact upon the current through the exercise zone. Furthermore, the reduced suction effects at the intake zone make the apparatus safer as objects are unlikely to be sucked onto or through the intake zone or related grid or screen.

Preferably the pump housing is of generally hollow tubular form having a circumferential wall and having the discharge-side outlet at one tubular end and the suction-side end wall at the other tubular end, with the suction-side inlet located on the circumferential wall at a longitudinal position between the pumping element and the suction-side end wall. Preferably the suction-side inlet extends for 180 degrees of the circumferential wall and extends longitudinally for a length greater than the radius of the pump housing. Preferably the suction-side inlet extends longitudinally for a length greater than the radius of the pump housing.

Advantageously, this can avoid losses associated with connecting the suction-side of the pump to narrow pipes. The suction-side of the pump is in direct fluid communication with a body of water held in the intake chamber. The suction-side inlet may be sized to have the same or greater cross-sectional area as the pump housing, avoiding throttling at the suction-side inlet. The intake chamber may be of large volume such that liquid may pass through it at a relatively low velocity. This can also avoid losses in comparison to connecting the suction-side of the pump to narrow pipes both by the fact that the liquid may travel at a lower velocity (and hence lower losses) and also that much of the liquid travels further from a solid surface than it would in a pipe. Preferably the liquid flow from the discharge-side outlet is substantially horizontal and is the centre of the discharge-side outlet is located 230 mm to 530 mm, preferably 380 mm, below an in-use level of liquid in the vessel.

Preferably the pump housing internal diameter is between 150 mm to 450 mm, preferably 300 mm.

Preferably the intake chamber extends the same width as the vessel, thus allowing an even greater volume in the chamber and allowing the intake zone to be of even greater area.

In an alternative embodiment the intake chamber extends the same width as the pump housing.

Preferably the intake chamber extends the same height as the vessel, or alternatively extends from the pump housing to the bottom of the vessel.

Preferably the intake zone is a generally vertical inlet.

Preferably the drive shaft extends substantially horizontally through the suction-side end wall to connect the pumping element to a drive means being an electric drive motor.

In one embodiment the guide means are a plurality of guide vanes that extend substantially radially in the discharge-side channel. Preferably the guide means are a pump stator member.

In one embodiment the intake chamber further includes intake guide means to assist in directing flow into and through the intake chamber.

Preferably an intake safety guard is provided for the liquid intake zone and/or an outlet safety guard is provided for the discharge-side outlet.

Preferably the intake safety guard and/or the outlet safety guard is a grid or grate member having openings therein to allow liquid to pass therethrough, and is of louvered form.

Optionally the intake safety guard includes at least one pressure sensitive switch operable to disable the drive means when the safety guard is touched.

Preferably the pumping element is a rotatable impeller.

Optionally, the apparatus includes the vessel. Preferably the vessel includes at least one sensor to detect at least one of a presence or absence of fluid in the vessel and to send an output signal used to enable or disable the drive means to prevent drive operation when the vessel contains no fluid. Optionally, the intake chamber may include such a sensor, preferably located at or near the suction-side inlet.

Preferably the pump has:

a) first and second bearings the shaft supported in the housing by the first and second bearings;

b) a bearing housing for supporting the first bearing; and

c) a thrust bearing mounted adjacent the first bearing;

and the guide means supporting the second bearing.

Preferably the vessel rests upon a foundation such as a concrete slab and optionally the vessel may be placed partially in ground. Preferably the motor is located aboveground. Preferably bracing means such as a stiffening rib or ‘A’-frame brace are provided to support the vessel walls.

BRIEF DESCRIPTION OF THE DRAWINGS

Other features and advantages of one or more preferred embodiments of the present invention will be apparent to one of ordinary skill in the art from the following written description with reference to and, used in conjunction, the accompanying drawings showing a preferred embodiment if the invention in which:

FIG. 1 is a cross-sectional view of a pump arrangement in accordance with a preferred embodiment of the present invention; and

FIG. 2 is a cross-sectional view of a vessel incorporating the apparatus 10 of FIG. 1.

DESCRIPTION OF PREFERRED EMBODIMENT

FIGS. 1 and 2 show cross-sectional views of apparatus for generating a current in a liquid containing vessel having an exercise zone.

The vessel 2 may be a swimming pool, spa bath or similar, containing water, chlorinated, salt or other treated liquid for swimming in, having an exercise or swimming zone 4 through which a current 8 flows. The terms ‘liquid’ and ‘water’ are hereinafter used in a generally interchangeable manner.

A swimmer (not shown) swimming in swimming zone 4 may swim against the current generated 8 to maintain a stationary position. Referring to FIG. 2, water is discharged from the pump 30 in a substantially horizontal direction from a point below the water surface level 6. A current 8 flows across the top or upper end of the vessel 2 as liquid is drawn back (generally counter-clockwise in the view of FIG. 2) through the axial pump 30 via an intake chamber 22 having an intake zone 24 at a lower end 26 of the intake chamber 22. The pump 30 is mounted at an upper end 28 of the intake chamber 22 and hence the horizontal discharge of liquid into the exercise zone 4 occurs near but below the surface 6 of the liquid in the vessel 2. The pump 30 draws liquid in an upward direction through intake chamber 22, from the intake zone 24.

The embodiment shown in the Figures includes the vessel 2 which forms the outer wall of the exercise zone 4 at one end, and forms the intake chamber inner wall 23 (having intake zone 24 and discharge zone 29) at the other end. Also integral with intake chamber inner wall 23 is intake chamber top wall 27. Mounted to the vessel 2 is the intake chamber outer wall 21 having a perimeter channel section or coping 18. Outer wall 21 and coping 18 may be integrally formed. Hence a shell 20 including the intake chamber 22 is formed. In the embodiment shown, the shell is constructed from fibreglass. The intake chamber 22 extends substantially vertically from the lower end of the vessel to the upper end of the vessel. Advantageously, the intake zone 24 is at the lower end 26 of the intake chamber 22, which ensures that the current 8 generated by the pump 30 and discharged from the pump 30 through discharge zone 29 flows without interference from the intake 24. The current 8 flows in one direction in the upper area of the vessel 2, and may gradually dissipate as the liquid flows generally counter-clockwise down one wall of the vessel 2 and then across the bottom of the vessel 2 to return to the intake chamber 22. The current 8 and returning liquid are thus vertically spaced apart. This enhances efficiency in current generation, reduces turbulence and provides a constant current 8 in the exercise zone 4 to the swimmer. It is noted that this constant current 8 may be varied upon demand by adjustment of control means (not shown) that may be provided on the pump or its motor.

The intake zone 24 includes a generally vertical inlet, in which a safety guard may be mounted such as a grid or grate member having openings therein to allow the liquid to pass through. The grid or grate member could be of louvred form. Preferably, the grid or grate is integrally formed in the intake chamber inner wall 23, by a method such as routing slots in the fibreglass wall to create the openings.

The free or open area (through which liquid may pass) of the intake zone 24 is as large or larger than the open or free area of the discharge zone 29. The intake zone 24 may include several grids or grates spaced apart. In the preferred embodiment, two rectangular grates each 700 mm wide and 600 mm high are provided integral the intake chamber inner wall 23, spaced 800 mm apart from each other and having routed slots in the fibreglass inner wall 23 of 8 mm high and 700 mm wide at 8 mm spacing, to create grates having 50% free area through which liquid may pass. By providing a large open free surface area in the intake zone, the suction effect in this area is low and the likelihood of objects being sucked onto the grates is low. As there is low suction in this area and the flow of liquid across the bottom of the pool is gentle, the swimmer obtains an experience of single directional current flow 8 from the discharge zone 29. In preferred embodiment the discharge zone also has a similar routed grate of 50% free area the grid being a circle of 300 mm diameter also having 8 mm high slots. In a preferred embodiment the centre of the discharge zone or outlet 29 is located 230 mm to 530 mm below the in-use level 6 of liquid in the vessel 2, and the pump housing 32 internal diameter is between 150 mm to 450 mm. Preferably, the centre of the discharge zone or outlet 29 is located 380 mm below the in-use level 6 of liquid in the vessel 2 and the pump housing 32 internal diameter is 300 mm. The vessel 2 is 2400 mm wide (at its lower end), 1300 mm deep and 5000 mm long (at its lower end). The intake chamber is a further 600 mm long (at its lower end). These dimensions provide an excellent swimming experience as the swimmer experiences a non-turbulent swimming current that is not affected by the returning liquid. This results in an effective and low turbulence current in the exercise zone 4 for the swimmer.

The intake chamber 22 may extend the full width of the vessel 2. In such a case, it is possible to provide a very large open or free area in the intake zone 24 at a distance remote from the discharge zone 29. Alternatively, the intake chamber 22 may extend the same width as the pump housing 32 (described below). In this case, the intake zone 24 still remains remote from the discharge zone 29. Where the intake chamber 22 has similar width to the vessel 2 (i.e. it extends for a greater width than the pump housing 32) water may be drawn in from either side of the vessel 2 and returned in an upward but also angled direction to the pump 30 to be discharged into the centre line of the vessel 2. Of course the pump 30 may be mounted off centre if desired but in general will be located on the centre line of the exercise zone 4. If several pumps are mounted in parallel, for example, any given pump may not be mounted on the centre line.

The pump 30 is located at an upper end 28 of the intake chamber 22. In the embodiment shown, the pump housing 32 resides inside the shell 20 formed by intake chamber inner wall 23, top wall 27 and outer wall 21. The intake chamber top wall 27 is located above the top of pump housing 32 so that the intake chamber 22 extends the same height as the vessel 2. The water level 6 is the same in both the vessel 2 and the chamber 22. In another embodiment, the intake chamber top wall 27 is located immediately above the pump housing 32 such that the chamber 22 does not extend the same height as the vessel 2. It is possible in a further alternative embodiment to mount the pump housing 32 externally of the intake chamber inner wall 23 and top wall 27 by providing a suitable hole in the top wall 27 and mounting the top wall 27 immediately below pump housing 32.

The pump 30 has an upstream suction-side 50 and a downstream discharge-side 60. The pump housing 32 is of generally hollow tubular form, having a circumferential wall in which is located a suction-side inlet 54, which is in fluid communication with intake chamber 22. The suction-side inlet 54 extends for 180 of the circumferential wall.

In the preferred embodiment the pump 30 has pump housing 32 and a shaft 40 of 28 mm diameter mounted on first bearings 42 and second bearings 44. The first bearings 42 are supported by a bearing housing 46 attached to suction-side end wall 56. Suction-side end wall 56 seals the pump housing 32 at one end.

The shaft 40 extends through first bearing 42 and through suction-side end wall 56 and is sealed with seal 57. A thrust bearing 48 is also provided. The first bearing 42 is supported by bearing mount 46.

In an alternative embodiment the shaft 40 has a larger diameter section 40B and two stepped sections one on either end 40A and 40C. A thrust bearing 48 and a bearing 42 are retained on stepped section 40A against the shoulder created by section 40B.

A pumping element 34 being a rotor or impeller is retained in fixed relation on shaft 40 (or in the alternative embodiment on shaft section 40C against stepped shaft section 40B). Downstream of pumping element 34 is guide means 36, being a stator. The stator 36 supports second bearing 44 and allows rotation of shaft 40 relative to stator 36. A retaining means 41 is located at the end of the shaft 40 to retain the rotor 34 and related bearing 42, together with pumping element 34 (in the alternative embodiment these are retained against the stepped shoulder created by section 40B). The retaining means 41 may be a nut or other 30 suitable retaining means.

The shaft 40 extending through suction-side end wall 56 may be coupled to a drive means 70. A drive mounting flange 74 may be mounted to the suction-side end wall 56 via bolts inserted into matching holes 58 and 76. The other side of the drive mounting flange 74 may be attached to a flange on an electric motor 70 via bolts inserted in holes 76. The shaft 40 of the pump 30 may be coupled to the drive shaft of the electric motor 70 via a coupling 72, such as a Lovejoy “C” type coupling. The motor may be a Leroy SOCR LSES 131SM flange mounted 5.5 hp 1453 rpm.

In order to ensure that the pump 30, electric motor 70 and mounting flange 74 are well supported, a pump mounting flange 14 is provided on intake chamber outer wall 21 for additional strength.

A plurality of stiffening ribs 25 in combination with brace supports 25 a form TV-frame supports to support the walls of the vessel 2 upon a foundation 3. Preferably the TV-frame 25, 25 a is bolted to the foundation 3 via bolts 25 b. The TV-frame extends from the underside of coping 18 and the rib 25 may be separately or integrally formed with the vessel wall. The ‘A’ frames may be spaced along each side of vessel/shell 20 eg at one metre intervals. Cladding may be applied between and attached to brace supports 25 a for aesthetic or protective reasons.

Water is drawn into the pump 30 via suction-side inlet 54, is propelled by rotor 34 to the discharge-side 60 of the pump 30 and passes through the stator 36 which functions as guide means. The guide means may be guide vanes or other arrangements. The guide means 36 direct the liquid to flow longitudinally of the shaft 40 in a discharge-side channel 62, substantially without swirling. This importantly ensures that the swimmer is not subject to turbulent swirling of water but rather to a steady flow of water current 8.

The pump housing 32 has a substantially horizontal discharge-side channel 62 having a open front end forming a discharge-side outlet 64. Water discharged through outlet 64 passes through discharge zone 29 into the exercise zone 4.

The top of coping 18 is higher than the top of pump housing 32. This enables the surface water level 6 to be higher than the top of pump housing 32. The horizontally discharged liquid of the current 8 may therefore be discharged at a distance below the water surface level 6. This advantageously avoids entrapment of air into the flow.

Preferably the top of perimeter channel or coping 18 is 230 mm above the top of pump housing 32, and the pump housing 32 has 300 mm diameter. The discharge-side outlet 64 has an open front end, however the discharge zone 29 has a smaller open area than the discharge-side outlet as it is located immediately adjacent the housing 32 and has a grid or grate member and thus less open area. The suction-side inlet 54 is relatively large and is positioned to allow liquid to be drawn into the pump 30 at a longitudinal position between the rotor 34 and the suction-side end wall 56. The suction-side inlet 54 extends 180° of the circumference of the pump housing 32. The suction-side inlet 54 has a longitudinal depth equivalent to the radius (r) of the pump housing. This results in a free open area of πr², being the same area as the open area of discharge-side outlet 64. Hence, while the axial pump 30 operates within a tube, it need only overcome minimal resistance or losses in comparison to those that could occur from supplying liquid to it via pipes or tubes, and the power used by driving the pump 30 is substantially used in providing a current 6 and overcoming the relatively minor losses caused by the safety grid mounted in discharge zone 29 and intake zone 24, rather than in overcoming pipe losses.

Further, because liquid through intake zone 24 will flow at a relatively low rate (as it will be possible to provide an intake zone free area much greater than πr²) losses can be expected to be very low through the vessel 2 and intake chamber 22. This results in a most efficient and therefore cheaper to run system. It also enables a relatively small motor to be used compared to where losses are high, also resulting in a capital cost saving.

The apparatus may conveniently be moulded in fibreglass in two pieces, one piece being the vessel 2 and a second piece being the intake chamber outer wall 21 incorporating perimeter channel 18. The width of perimeter channel 18 and intake chamber outer wall 21 maybe selected as desired and matched to vessel 2 and pump housing 32. In assembly, vessel 2 may be laid in position and the intake chamber outer wall 21 may then be mounted. The pump 30 including pump housing 32 is then mounted on a third piece being a pump mounting flange 14 that is attached to outer wall 21 in register with a hole of suitable diameter. The pump is secured via bolts is inserted in hole 15 and suction-side end wall 56 and pump housing 32.

In one alternative embodiment not shown, guide vanes may be provided in intake chamber 22, preferably mounted on chamber inner wall 23 for ease of fabrication.

In a preferred embodiment, not shown, the liquid intake zone 24 has a safety guard including at least one pressure sensitive switch operable to disable the electric motor when the safety guard is touched. Hence, if for example a child dives to the liquid intake zone and attempts to remove same, the pump will be stopped and danger averted.

In another embodiment, one or more sensors may be provided in the vessel or the intake chamber, whereby the pump stops operating or will not start operating unless water is detected by the sensor.

In a further alternative embodiment, not shown, apparatus may be provided in a retro-fit format whereby the intake chamber and pump housing 32 are mounted at one end of an existing vessel 2.

The preferred embodiment of the invention provides for an above ground swimming vessel which may be installed in a backyard, garage or other convenient location on a temporary or permanent basis, having excellent swimming characteristics. 

1. Apparatus for generating a current in a liquid-containing vessel having an exercise zone for a swimmer, the apparatus including: a) a shell, the shell including an upwardly extending intake chamber in fluid communication with the vessel, the intake chamber having a liquid intake zone located in a lower end of the intake chamber; b) an axial pump having an upstream suction-side and a downstream discharge-side, the pump located at an upper end of the intake chamber, the pump having: i) a pump housing having a suction-side inlet in fluid communication with the intake chamber, a substantially horizontal discharge-side channel having an open front end forming a discharge-side outlet, and a suction-side end wall remote from the suction-side inlet and discharge-side outlet; ii) a substantially horizontal drive shaft defining a longitudinal axis of the pump; iii) a pumping element for expelling liquid via the discharge-side channel and discharge-side outlet into the exercise zone; iv) a guide means arranged to direct liquid to flow longitudinally in the discharge-side channel substantially without swirling, the guide means being located downstream of the pumping element; c) drive means adapted to drive the drive shaft, wherein driving the drive shaft produces a discharge of liquid through the discharge-side outlet, to create a current in the exercise zone for a swimmer to swim against.
 2. Apparatus according to claim 1 wherein the pump housing is of generally hollow tubular form having a circumferential wall and having the discharge-side outlet at one tubular end and the suction-side end wall at the other tubular end, with the suction-side inlet located on the circumferential wall at a longitudinal position between the pumping element and the suction-side end wall.
 3. Apparatus according to claim 2 wherein the suction-side inlet extends longitudinally for a length greater than the radius of the pump housing.
 4. Apparatus according to claim 3 wherein the suction-side inlet extends for 180 degrees of the circumferential wall.
 5. Apparatus according to claim 1 wherein the fluid flow from the discharge-side outlet is substantially horizontal and the centre of the discharge-side outlet is located 230 mm to 530 mm below an in-use level of liquid in the vessel.
 6. Apparatus according to claim 2 wherein the pump housing internal diameter is between 150 mm to 450 mm.
 7. Apparatus according to claim 1 wherein the intake chamber extends the same width as the vessel.
 8. Apparatus according to claim 1 wherein the intake chamber extends the same width as the pump housing.
 9. Apparatus according to claim 1 wherein the intake chamber extends the same height as the vessel and the intake zone is a generally vertical inlet.
 10. Apparatus according to claim 1 wherein the drive means is an electric drive motor, wherein the drive shaft extends substantially horizontally through the suction-side end wall to connect the pumping element to the electric drive motor.
 11. Apparatus according to claim 1 wherein the guide means are a plurality of guide vanes.
 12. Apparatus according to claim 11 wherein the guide vanes extend substantially radially in the discharge-side channel.
 13. Apparatus according to claim 1 wherein the guide means is a pump stator member.
 14. Apparatus according to claim 1 wherein the intake chamber further includes intake guide means.
 15. Apparatus according to claim 1, wherein an intake safety guard is provided for the liquid intake zone or an outlet safety guard is provided for the discharge-side outlet.
 16. Apparatus according to claim 15 wherein the intake safety guard or the outlet safety guard is a grid or grate member having openings therein to allow liquid to pass therethrough.
 17. Apparatus according to claim 16 wherein the intake safety guard or the outlet safety guard is a grid or grate member of louvered form.
 18. Apparatus according to claim 15 wherein the intake safety guard includes at least one pressure sensitive switch operable to disable the drive means when the safety guard is touched.
 19. Apparatus according to claim 1 further including the vessel.
 20. Apparatus according to claim 19, wherein the vessel includes at least one sensor to detect at least one of a presence or absence of fluid in the vessel and to send an output signal to enable or disable the drive means to prevent drive operation when the vessel contains no fluid. 